Android SQLite basic operation

Create a new Class (Ex:userdbhelper) inheritance Sqliteopenhelper

• Constructor built-in database

    Public Userdbhelper (context context, int version) {        Super (context, db_name,null,version);    }

• OnCreate method inside the table is built

     /**     * is only called when the database is generated, generally we will     build a table in this method     * @param sqlitedatabase */    @Override public    Void OnCreate (Sqlitedatabase sqlitedatabase) {        log.d (TAG, "onCreate:");        String drop_table = "drop table IF EXISTS" + table_name + ";";        LOG.D (TAG, "oncreate:drop_table_sql" + drop_table);        Sqlitedatabase.execsql (drop_table);        String create_sql = "Create TABLE IF not EXISTS" + table_name + "(" +                "_id INTEGER PRIMARY KEY autoincrement not NUL L, ' +                ' name VARCHAR NOT NULL, ' + ' age INTEGER not NULL, ' +                ' height LONG not null, ' + ' weight FLOAT not null, ' +< c15/> "married INTEGER not NULL," + "update_time varchar is not NULL" +                 ", phone VARCHAR, password varchar" +                ");";        log.d (TAG, "crate_table sql:" +create_sql);        Sqlitedatabase.execsql (Create_sql);    }

• Onupgrade method inside is to upgrade the database table

  @Override public    void Onupgrade (sqlitedatabase sqlitedatabase, int oldversion, int newversion) {        log.d (TAG, " onupgrade:oldversion= "+oldversion+" newversion: "+newversion);        if (NewVersion > 1) {            String alertsql = "ALTER TABLE" + table_name + "ADD COLUMN phone VARCHAR;";            LOG.D (TAG, "onupgrade:alertsql=" +alertsql);            Sqlitedatabase.execsql (alertsql);            Alertsql = "ALTER TABLE" + table_name + "ADD COLUMN password VARCHAR;";            LOG.D (TAG, "onupgrade:alertsql=" +alertsql);            Sqlitedatabase.execsql (Alertsql);        }    }
  
  
  

  Package com.safeluck.floatwindow.db;
  
  Import android.content.ContentValues;
  Import Android.content.Context;
  Import Android.database.sqlite.SQLiteDatabase;
  Import Android.database.sqlite.SQLiteOpenHelper;
  Import Android.util.Log;
  
  Import java.util.List;
  
  /**
  * AAA
  * Created by LZW on 2018/8/23. 15:28:33
  * Email: [Email protected]
  * All Rights saved! Chongqing Anyun Tech Co. LTD
  */
  public class Userdbhelper extends Sqliteopenhelper {
  private static final String db_name = "UserDB";
  private static final int db_version = 1;
  private static Userdbhelper Mhelper;
  Private static final String table_name = "user";
  private static final String TAG = "Userdbhelper";
  Private sqlitedatabase DB = null;
  Public Userdbhelper (context context, int version) {
  Super (context, db_name,null,version);
  }
  
  public static Userdbhelper getinstance (Context context,int version) {
  if (version>0 && mhelper = = null) {
  Mhelper = new Userdbhelper (context,version);
  }else if (mhelper = = null) {
  Mhelper = new Userdbhelper (context,db_version);
  }
  return mhelper;
  }
  
  
  /**
  * Get a read-only database
  * @return
  */
  Public Sqlitedatabase Getreadlink () {
  DB = Mhelper.getreadabledatabase ();
  return DB;
  }
  
  Public Sqlitedatabase Getwritedb () {
  DB = Mhelper.getwritabledatabase ();
  return DB;
  }
  
  /**
  * Called only when the database is generated, generally we will
  * The table is built in this method
  * @param sqlitedatabase
  */
  @Override
  public void OnCreate (Sqlitedatabase sqlitedatabase) {
  LOG.D (TAG, "onCreate:");
  String drop_table = "drop table IF EXISTS" + table_name + ";";
  LOG.D (TAG, "oncreate:drop_table_sql" + drop_table);
  Sqlitedatabase.execsql (drop_table);
  
  String create_sql = "Create TABLE IF not EXISTS" + table_name + "(" +
  "_id INTEGER PRIMARY KEY autoincrement not NULL," +
  ' name VARCHAR NOT NULL, ' + ' age ' INTEGER not NULL, ' +
  "Height LONG is not null," + "weight FLOAT is not null," +
  ' Married INTEGER not null, ' + ' update_time VARCHAR not NULL ' +
  ", phone varchar, password varchar" +
  ");";
  LOG.D (TAG, "crate_table sql:" +create_sql);
  Sqlitedatabase.execsql (Create_sql);
  }
  
  @Override
  public void Onupgrade (sqlitedatabase sqlitedatabase, int oldversion, int newversion) {
  LOG.D (TAG, "onupgrade:oldversion=" +oldversion+ "newversion:" +newversion);
  if (NewVersion > 1) {
  String alertsql = "ALTER TABLE" + table_name + "ADD COLUMN phone VARCHAR;";
  LOG.D (TAG, "onupgrade:alertsql=" +alertsql);
  Sqlitedatabase.execsql (Alertsql);
  Alertsql = "ALTER TABLE" + table_name + "ADD COLUMN password VARCHAR;";
  LOG.D (TAG, "onupgrade:alertsql=" +alertsql);
  Sqlitedatabase.execsql (Alertsql);
  
  }
  
  }
  
  /**
  * Delete a row of data
  * @param condition
  */
  public void DeleteRow (String condition) {
  Db.delete (Table_name,condition,null);
  }
  
  
  Public long AddUser (list<userinfo> Userinfos) {
  Long reuslt =-1;
  for (int i = 0; i < userinfos.size (); i++) {
  UserInfo info = userinfos.get (i);
  Contentvalues CV = new Contentvalues ();
  Cv.put ("name", Info.name);
  Cv.put ("Age", info.age);
  Cv.put ("height", info.height);
  Cv.put ("Weight", info.weight);
  Cv.put ("Married", Info.married);
  Cv.put ("Update_time", info.update_time);
  Cv.put ("Phone", info.phone);
  Cv.put ("password", Info.password);
  REUSLT = Db.insert (table_name, "", CV);
  }
  LOG.D (TAG, "adduser:result=" +reuslt);
  return reuslt;
  }
  
  }

Android SQLite basic operation